Theresa May holding hands with Donald Trump was seen to confirm the continuing 'special relationship' with the USA, but it was a Scottish diplomat and his wife who helped forge it in the first place.

That they did so in the aftermath of a bitter war between Britain and its one-time American colonists, underlines the magnitude of their achievement.Their remarkable story is now being told at the National Library of Scotland (NLS) in Edinburgh.

In 1796, only 13 years after the two nations fought against each other in the American War of Independence, Henrietta Liston arrived in Philadelphia with her husband, Robert, who had been born in Kirkliston, West Lothian. He had just been appointed British Minister to the US. By the end of their four-and-a-half year posting, they had won the trust and admiration of leading government figures including the first President George Washington. Historians describe it as a triumph of personal charm and cultured diplomacy.

Henrietta’s handwritten North American journals, which are part of the Library’s Liston papers archive, are now being made available online to mark International Women’s Day today (March 8).

In the Liston papers are invitations to the couple to dine with George Washington and his wife Martha and an invitation to the funeral oration of the former President after his sudden death in 1799. The esteem in which the Listons were held is demonstrated by Henrietta when she writes about the celebratory dinner to mark Washington’s retirement. “I had, as usual, the gratification of being handed to table and of sitting by the President.”

It was a turbulent time as the United States sought to establish itself as an independent nation. Relations with France, its wartime ally against the British, soured and Henrietta wrote of the prospect of war between the two former allies. “So violently does the tide now flow in favour of the English nation & against the French, – that there are moments when I think Magic-art must have worked it.”

It would be almost 150 years before the term “special relationship” would be coined by Winston Churchill to describe the bond between the two nations but Frank Cogliano, Professor of American History at the University of Edinburgh, said: ” We have a hint of what is to come in the relationship between the Listons and the Washingtons in particular and the United States more generally.”

Henrietta, or Hennie as she was known, was born in Antigua to a family of Scots descent. Orphaned by the age of 10, she and her brothers were sent to live with an uncle and aunt in Glasgow where she grew up. She was 44 when she married Robert Liston, departing for the United States almost immediately.

Her writings record observations on the major figures who established the United States including Founding Fathers, Thomas Jefferson, John Jay, Benjamin Rush, and Alexander Hamilton. “Henrietta’s friendship with Washington reflects how successful the Listons were in repairing the relationship between Britain and the US at this very uncertain and unstable time,” said Dora Petherbridge, the NLS’s Curator of US and Commonwealth collections.

“She writes about sitting between the rising sun, Adams, who was to be the second president, and the setting sun, Washington, and she says she feels perfectly easy and familiar with both great men. This is extraordinary for a woman at this time to feel that ease in front of such political power.”

The Listons travelled extensively, including trips into Canada and the Caribbean. They covered thousands of miles by stagecoach, canoe, ship and carriage. These travels are represented on an interactive map which is part of the new online resource.